Substrate Integrated Waveguide Cavity-backed Patch Research Articles

High-Gain Millimeter-Wave Patch Array Antenna for Unmanned Aerial Vehicle Application.

A high-gain millimeter-wave patch array antenna is presented for unmanned aerial vehicles (UAVs). For the large-scale patch array antenna, microstrip lines and higher-mode surface wave radiations contribute enormously to the antenna loss, especially at the millimeter-wave band. Here, the element of a large patch array antenna is implemented with a substrate integrated waveguide (SIW) cavity-backed patch fed by the aperture-coupled feeding (ACF) structure. However, in this case, a large coupling aperture is used to create strongly bound waves, which maximizes the coupling level between the patch and the feedline. This approach helps to improve antenna gain, but at the same time leads to a significant level of back radiation due to the microstrip feedline and unwanted surface-wave radiation, especially for the large patch arrays. Using the SIW cavity-backed patch and stripline feedline of the ACF in the element design, therefore, provides a solution to this problem. Thus, a full-corporate feed 32 × 32 array antenna achieves realized gain of 30.71–32.8 dBi with radiation efficiency above 52% within the operational band of 25.43–26.91 GHz. The fabricated antenna also retains being lightweight, which is desirable for UAVs, because it has no metal plate at the backside to support the antenna.

Design of Physically Connected Wideband SIW Cavity-Backed Patch Antenna for Wide-Angle Scanning Phased Arrays

A novel wideband substrate integrated waveguide (SIW) cavity-backed antenna element and its array are proposed in this letter. The proposed linearly polarized array element consists of a SIW cavity, stacked patches, and a coaxial probe. The SIW cavity-backed array element is implemented with physically connected stacked patch. The coaxial pin is directly connected to the two patch radiators. Blind and buried vias were avoided, this work significantly reduces the manufacture cost and complexity. The array features light weight and simple feed structure. The proposed element exhibits an impedance-matching bandwidth of 18.2% (14.5–17.4 GHz) for | S 11| H -plane with 8% bandwidth (14.4–15.6 GHz), under the criterion of active voltage standing- wave ratio (VSWR) ≤ 3. For verification purposes, a 4 × 16 active phased array antenna prototype is fabricated using the conventional microwave multilayer printed circuit board (PCB) process. The measured results agree very well with simulations.

A Wideband High-Gain Planar Integrated Antenna Array for $E$ -Band Backhaul Applications

A novel wideband high-gain planar antenna array for $E$ -band backhaul applications is presented in this article. The antenna element is composed of a substrate integrated waveguide (SIW) cavity-backed patch and a stepped waveguide horn. The SIW cavity-backed patch is worked as wideband waveform and impedance transformer to excite the stepped waveguide horn on the upper layer. The stepped waveguide horn is employed to enhance the gain of the antenna element by increasing the radiation aperture. Based on the proposed antenna element, a $2 \times 2$ subarray with element spacing larger than a wavelength is designed. A groove, which works as secondary radiation source, is etched between the elements to improve the gain and suppress the high sidelobes of the $2 \times 2$ subarray. By taking the advantage of the groove, the $2 \times 2$ subarray achieves a maximum boresight gain of 17 dBi and an −10 dB impedance bandwidth of 21.8% from 70 to 87 GHz. For further enhancing the gain, a prototype including $16 \times 16$ elements is manufactured and measured. The experimental results confirm that the proposed antenna achieves the −10 dB impedance bandwidth of 22.4% from 71 to 88.5 GHz and a peak gain of 28.8–30.9 dBi. With the merits of a wider operating bandwidth, high gain, low profile, and low cross-polarization, the proposed antenna array is suitable for application in the $E$ -band wireless backhaul systems.

Textile Microwave Components in Substrate Integrated Waveguide Technology

Although substrate integrated waveguide (SIW) technology is well established for the fabrication of microwave circuits on rigid printed circuit boards, and the first implementations of textile SIW antennas have recently appeared in literature, up to now, no complete set of SIW microwave components has been presented. Therefore, this paper describes the design, manufacturing, and testing of a new class of textile microwave components for wearable applications, implemented in SIW technology. After characterizing the adopted textile fabrics material in terms of electrical properties, it is shown that folded textile SIW components, such as interconnections, filters, and antennas form excellent building blocks for wearable microwave circuits, given their low profile, flexibility, and stable characteristics under bending and in proximity of the human body. Hence, they allow the full exploitation of the large area garments offered for the deployment of wearable electronics. Besides SIW interconnections, a folded textile SIW filter operating at 2.45 GHz is designed and tested. The filter combines excellent performance in the band of interest with good out-of-band rejection, even when accounting for the tolerances in the fabrication process. Finally, a folded SIW cavity-backed patch antenna is fabricated and experimentally verified in realistic operating conditions.